Part A:
1. Mix 35mL of pure ethanol in 65mL of water (total: 100mL): 35% concentration
2. Pour the mixture in the flask
3. Put a 1-hole-stopper on the opening of the flask
4. Put the temperature probe through one hole of the stopper in step 3
5. Connect the probe to the sensor and to the computer
6. Put the tube through the other hole of the stopper in step 3
7. Prepare a beaker filled with ice
8. Put the test tube in the ice
9. Put a 1-hole-stopper on the opening of the test tube
10. Put a tube through the hole of stopper in the step 9
11. Heat the water / mixture
12. Record the temperature of water / mixture over time on the computer using the sensor
13. Record the temperature of water / mixture that remains constant (boiling point)
Experimnta Set-up of Part B
Part B:
1. Take the distillation of liquid gathered in the test tube and pour into a crucible
2. Measure the mass and volume of liquid using digital balance
3. Burn the liquid using the match
4. Measure the mass and volume of liquid left after burning and calculate the density
5. Use the data of step 4 to calculate the mass, volume, and density of liquid that burned away
Hypothesis
Part A:
I expect the temperature of mixture would stop and remain constant at about 85 C, because ethanol has lower boiling point than water does. Therefore, when alcohol and water are mixed together, it would have the boiling point which would be between water’s and ethanol's boiling point. The more I add alcohol to water the more the boiling point would be closer to that of ethanol.
Part B:
I expect the liquid distilled from Part A to have a density of pure Ethanol (0.789g/mL). It will be because ethanol will be vaporized first with its lower boiling point.
Result
Part A:
Temperature over time when Boiling the mixture
When boiling the mixture, it seemed to remain constant temperature at 85 C. When the temperature remains constant, it would mean that the boiling point has reached. Compared to pure water boils at 100 C, the mixture boiled at 85 C. According to my research, ethanol boils at 78.4 C. Since the 35% concentrated mixture decreased the boiling temperature by 15 C, higher concentration of mixture would further decrease the boiling temperature.
Relationship Between Concentration of Mixture and Boiling Point
Part B:
Liquid Distilled out From Part A:
Volume (mL)
Mass (g)
Density (g/mL)
34.3
28.64
0.835g/mL
Experiment of Crucible;
Liquid
Volume (mL)
Mass (g)
Density (g/mL)
Original Liquid
2.5
2.25
0.9
Liquid Remained After Burning
1.2
1.06
0.88
Liquid Burned (estimated)
1.3
1.19
0.91
According to the Simple Theory
The liquid distilled out from Part A should have a density of pure Ethanol, which is 0.789g/mL. It would be because the ethanol which has lowe boiling point would vaporize faster than water. Therefore, only the pure ethanol would have been gathered through ditillation.
If the theory above didn't work, the liquid reainedurned in the crucible should have the density of water, which is 1g/mL. Moreover, the expected density of liquid burned should have been that of ethanol (0.789g/mL).
Science Behind the Experiment
Ethanol and water mixed together is a homogeneous mixture. It is not chemically blended but rather physically. Therefore, the solution can be seperated through distillation. However, if the mixture was chemically blended, it would have only been seperated by chemical reaction.
Homogenoeous Mixture
According to my reserch, ethanol has a lower boiling point (78.4 C) than that of water (100 C). It's because ethanol has a lower intermolecular forces than water does, which is the forces holding molecules together. Therefore, when water and ethanol mix together, boiling point would get lower than 100 C.
Evaluation
For Part A, in determining the relationship between concentration of ethanol boiling point, there were two points to make more accurate result. Therefore, if I can do this experiment again next time, I would try an experiment with more various concentration of ethanol.
For Part B, the result of density of burned and remained liquid was not consistent over several trials. Therefore, if I can do this experiment again next time, I would try to use as little amount of liquid as possible (because it helps to improve the precision). Moreover, since solution was well mixed, I think there would have remained some ethanol that didn't burned. Therefore, next time, I can make the liquid sit there for few minutes, and then do the burning.
Boiling Point of Mixture (Ethanol & Water)
Materials
Variables
- Mixtures
o Water + EthanolProcedure
Part A:
1. Mix 35mL of pure ethanol in 65mL of water (total: 100mL): 35% concentration
2. Pour the mixture in the flask
3. Put a 1-hole-stopper on the opening of the flask
4. Put the temperature probe through one hole of the stopper in step 3
5. Connect the probe to the sensor and to the computer
6. Put the tube through the other hole of the stopper in step 3
7. Prepare a beaker filled with ice
8. Put the test tube in the ice
9. Put a 1-hole-stopper on the opening of the test tube
10. Put a tube through the hole of stopper in the step 9
11. Heat the water / mixture
12. Record the temperature of water / mixture over time on the computer using the sensor
13. Record the temperature of water / mixture that remains constant (boiling point)
Part B:
1. Take the distillation of liquid gathered in the test tube and pour into a crucible
2. Measure the mass and volume of liquid using digital balance
3. Burn the liquid using the match
4. Measure the mass and volume of liquid left after burning and calculate the density
5. Use the data of step 4 to calculate the mass, volume, and density of liquid that burned away
Hypothesis
Part A:I expect the temperature of mixture would stop and remain constant at about 85 C, because ethanol has lower boiling point than water does. Therefore, when alcohol and water are mixed together, it would have the boiling point which would be between water’s and ethanol's boiling point. The more I add alcohol to water the more the boiling point would be closer to that of ethanol.
Part B:
I expect the liquid distilled from Part A to have a density of pure Ethanol (0.789g/mL). It will be because ethanol will be vaporized first with its lower boiling point.
Result
Part A:
When boiling the mixture, it seemed to remain constant temperature at 85 C. When the temperature remains constant, it would mean that the boiling point has reached. Compared to pure water boils at 100 C, the mixture boiled at 85 C. According to my research, ethanol boils at 78.4 C. Since the 35% concentrated mixture decreased the boiling temperature by 15 C, higher concentration of mixture would further decrease the boiling temperature.
Relationship Between Concentration of Mixture and Boiling Point
Part B:
Liquid Distilled out From Part A:Experiment of Crucible;
According to the Simple Theory
Science Behind the Experiment
Ethanol and water mixed together is a homogeneous mixture. It is not chemically blended but rather physically. Therefore, the solution can be seperated through distillation. However, if the mixture was chemically blended, it would have only been seperated by chemical reaction.According to my reserch, ethanol has a lower boiling point (78.4 C) than that of water (100 C). It's because ethanol has a lower intermolecular forces than water does, which is the forces holding molecules together. Therefore, when water and ethanol mix together, boiling point would get lower than 100 C.
Evaluation
For Part A, in determining the relationship between concentration of ethanol boiling point, there were two points to make more accurate result. Therefore, if I can do this experiment again next time, I would try an experiment with more various concentration of ethanol.For Part B, the result of density of burned and remained liquid was not consistent over several trials. Therefore, if I can do this experiment again next time, I would try to use as little amount of liquid as possible (because it helps to improve the precision). Moreover, since solution was well mixed, I think there would have remained some ethanol that didn't burned. Therefore, next time, I can make the liquid sit there for few minutes, and then do the burning.
Resources
http://www.siraze.net/chemistry/sezennur/subjects/experiment/004.pdf (source of experiment idea)http://www.chem.purdue.edu/gchelp/liquids/boil.html (Science behind the experiment)
http://www.science.uwaterloo.ca/~cchieh/cact/c123/intermol.html (Science behind the experiment)
Additional Information
Ethanol
Other names: Ethyl alcohol; grain alcohol; pure alcohol; hydroxyethane; drinking alcohol; ethyl hydrate
Molecular formula: C2H6O
Molar mass: 46.06844(232) g/mol
Appearance: colorless clear liquid
Density: 0.789 g/mL
Melting point: −114.3 °C (158.8 K)
Boiling point: 78.4 °C, 173.1 F (351.6 K)
Solubility in water: Fully miscible
http://en.wikipedia.org/wiki/Ethanol
At the boiling point, saturated vapor pressure equals atmospheric pressure
http://hyperphysics.phy-astr.gsu.edu/Hbase/Kinetic/vappre.htmlhttp://cache.eb.com/eb/image?id=72150&rendTypeId=35
Plan and Material List
Revised Plan and Material List
Observation
Graph